


Deuteronomy 27:22

by Nisaki



Category: Kuroshitsuji | Black Butler
Genre: First Time, M/M, Pseudo-Incest, SebaCiel - Freeform, Smut, sebastian and Ciel are stepbrothers
Language: English
Status: Completed
Published: 2018-02-25
Updated: 2018-02-25
Packaged: 2019-03-23 15:50:45
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,281
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13791000
Author URL: https://archiveofourown.org/users/Nisaki/pseuds/Nisaki
Summary: On Sunday service, the priest talked about crimson hell fire and molten metal and heated chains. Sebastian knew; hell fire wasn't red but deep blue, lurking in the eyes of a thirteen years old boy.His little brother.





	Deuteronomy 27:22

**Author's Note:**

  * For [Miyukiki](https://archiveofourown.org/users/Miyukiki/gifts).



> Happy birthday to my wonderful friend Miyukiki! I've been blessed with another year of your friendship. May this year be better than the previous one.  
> This is a little gift for you, and I hope you enjoy it.

It was a hot summer's day when Sebastian's mom sobered long enough to fall in love. Her cheeks weren't flushed from too many drinks and her eyes started shining again like when Sebastian was six and she used to pet his hair and call him Seb.

In fall, he met the guy for the first time; he's got blue, sharp eyes and bangs styled to the side, a mole on his cheek and a sweet smile on his face. Rachel's heart in his hand and a ring on her finger.

This man had just asked Sebastian's mother to marry him and Rachel said yes.

Sebastian wasn't paying attention to all of that, but to the sweet boy who was using his father as a shield; Ciel, Rachel said ''Your new brother,''

She said it like Sebastian was four and still demanding his twenty years old mom to get him a sibling. Like Sebastian was supposed to be ecstatic, he wasn't so happy about his ''new brother'' but he was glad his mom was catching a break. She deserved it.

Later when he left for his third year in college, he'd only seen Ciel twice. For some reason, the boy stayed on his mind.

Rachel became an official Phantomhive in the spring's break. With two people working, they got a bigger house, and Sebastian got the room with the balcony and everything was going well.

Till the summer Ciel became thirteen.

 

* * *

 

 

During his summer vacation Sebastian took a job at a bar, which meant he stayed home with Ciel while their parents worked and left in the evenings. ''Take care of your brother,'' Rachel told him before she closed the door.

The first day alone with Ciel didn't go as planned, Sebastian tried to talk to him, engage him in some kind of brotherly activity, suggested they go to the park. Ciel looked at him with big blue eyes and cocked his head to the side, hair sliding on his forehead and falling over his eyes.

''You want to take me out?''

The tone was innocent enough, but the curl of a smile on Ciel's lips was almost a sneer. Sebastian paused. Nodded. Ciel laughed.

Ciel walked to him and leaned close, lips right beside Sebastian's ear. He whispered the words like they were a secret. ''You're cute,''

Sebastian didn't have the time to react before Ciel pulled back and walked away, proceeding to ignore him for the rest of the day. 

 

* * *

 

 

The summer grew hotter and with the rising heat Ciel's clothing got more and more revealing. Sebastian didn't think much of it at first, perhaps that was his first mistake.

It got harder than it should, for Sebastian to not look. Ciel's exposed skin drew his gaze, a magnetic force that Sebastian couldn't get out of its orbit.

Ciel was his baby brother, was thirteen. Sebastian kept repeating in his head. Ciel kept shedding cloth, exposing more flesh and Sebastian grew desperate. He wasn't the one for mad lust, but late at night, he dreamt of candy lips and creamy skin. Sweet kisses and soft curves.

On Sundays he prayed. God didn't save him.

 

* * *

 

 

For the most part Sebastian didn't exist in Ciel's world. He was too busy (reading, watching TV, doing nothing) to look at Sebastian. A little mercy or another form of torture, Sebastian was not sure.

Then Ciel decided to pay him attention and the world tipped over its axis, stopped. The universe circled the delicate round of Ciel's waist. Sebastian's gave up his mind, but when cerulean eyes shined at him with devilish glint, Sebastian lost his heart too.

It was 103 degrees and Ciel was wearing Sebastian's shirt. ''It's cooler,'' was his answer to Sebastian's questioning gaze.  Too big, the collar slid down one of Ciel's shoulders, flawless, ivory curve on display. Too small to cover skinny legs, the shirt looked like the most obscene article of clothes Sebastian had ever seen.

Ciel wore it for days in a row.

Sebastian was hanging to the last threads of his sanity. Slept with the bible held into his chest, and chants of _he's your little brother_ in his brain. Still his sleep was weighed by visions of Ciel.

It only got worse.

 

* * *

 

 

''You have to help me,'' Ciel whined. Sebastian was hoping he wouldn't be tortured today, but Ciel had other ideas. Wearing another shirt of Sebastian and carrying a polish bottle in his hand, the little boy strolled and draped himself on Sebastian's lap.

''I can't paint the other hand,'' His big eyes, glittering with fault innocent, stared up at Sebastian. His mouth went dry, his heart beat tripled. Ciel's smile took a menacing edge.

Small, devilish red nails offered him the bottle, Sebastian's hand trembled as he took the tiny, colorless hand in his. Hypnotized, he stroked the brush over Ciel's nails. It was the colour of blood, and maybe this was what Ciel's hands would look like when he ripped Sebastian's heart out.

Ciel smelled like cherries. He was warm, light as a feather on Sebastian's thighs.

''There. All done,'' His tone wasn't shaky, and for that he was thankful. Ciel, never a fan of bravado, tipped his head up, kissed Sebastian right on the mouth. Giggled.

Sebastian's chest tightened. Grateful the kiss was short as a whisper, yet mourning the fleeting touch. He didn't get to taste.

When his reverie ended, Ciel was no longer there.

 

* * *

 

On Sunday service, the priest talked about crimson hell fire and molten metal and heated chains. Sebastian knew; hell fire wasn't red but deep blue, lurking in the eyes of a thirteen years old boy.

His little brother. 

Around dinner table Rachel said a prayer, Ciel's toes were making their way up on Sebastian's leg, his cock fattening for what might've been the tenth time that day.

She thanked the lord when Sebastian creamed his jeans, looking the devil in the eye.

 

* * *

 

 

The fall hang in the distance like an oasis, Sebastian's desert was the most beautiful boy ever. Day by day, Sebastian fell apart. He left trails of red as his heart bled and bled.

Ciel's white clothes never got stained.

He walked barefoot. Little, pristine feet hitting the ground like the flutter of a baby bird wing. It made him appear ethereal, on another plane of existence. Walked with his back turned to everything, untouchable.

Sebastian wished for the shreds of his broken soul to lay on the floor, wished for the shattered pieces to make Ciel’s feet bleed. A mark to prove he was there at a point in Ciel’s life, more than just a fool lolling out his tongue at Ciel’s trail.

By the time his summer had only few days left, Sebastian was living for the ghost touches of delectate fingers and sweet nectar from prohibited lips. He only needed few more days worth of patience, and college will save him.

''Would you buy me a ring?'' Ciel's feet were swaying in the air, small of his back on display where his shirt rode up, only underwear beneath. Sebastian's eyes followed the swell of his small ass, and he swallowed. Throat always tight when Ciel was around.

''Hmm?''

Ciel giggled ''You're so silly,'' his sigh exaggerated ''Would you buy me a ring, Sebastian?'' Ciel looked right at him, eyes blue enough to suffocate him up.

Ring?

''Do you want one?''

Ciel nodded ''Daddy says people who have sex before marriage go to hell. So you have to buy me a ring,''

Sebastian choked on air, heart started a crescendo. Foolish hope and hot desire shooting through him like thunder. Hell.

''Vincent didn't tell you? Men who sleep with children go to hell, too.'' his tone is bitter, he maybe didn't care. He was at the point where he would go to hell either way. Might as well get something on the way there.

''I'm not sleeping with a child,'' Ciel's smile has a sharp edge; devilish. ''You are,''

He got to his hands and knees, crawled the space between them and sat at Sebastian's feet. Sebastian should be the one down, he was the worshiper, the supplicant. Ciel stared up at him, curve of his lips sinister. Sebastian was scared of this boy. And he was in love.

So he did the only thing that made sense to him. He got down on his knees too, reached out to Ciel for the first time ever, held him. Ciel was so small, almost swallowed whole by Sebastian's arms, so frail he was afraid to embrace him hard. He smelled sweet, like a new start; the changing of seasons.

''I'll buy you everything you want.''

Ciel hummed against his neck, his warm breath raising goosebumps on Sebastian's skin. The shivers ran up and down his spine, Ciel melted into him, draped himself on Sebastian's lap.

It was finally time to give up.

The first kiss burned bright behind his eyelids, tasted like sin, promised crimson flames. Sebastian lunged his tongue into Ciel's mouth, sucking Ciel's tongue and drinking his saliva. So sweet. The way Ciel responded to him, the fine tremors shaking his petite body.

Sebastian kissed him till they both lost their breath, till his lips were almost as tender as his heart. He trailed feather like kisses down the curve of Ciel's neck, sucked on the swell of his shoulder that drove him mad thousands of times before. He wanted so bad to leave marks, but he couldn't, not here were they could be seen.

Ciel's back hit the ground and he moaned, eyes half lidded staring up at Sebastian with desire that boiled his blood, and set his soul on fire. His hands slid up on Ciel's waist, taking the shirt with them till he got it off. Ciel lifted his hips in invitation and Sebastian lost his breath when the last article of Ciel's clothes fell aside. His tiny arousal was flushed and hard, dripping at the top. It was in Sebastian's mouth before he took the next breath, Ciel's almost shout filling his ears as he swallowed him down and sucked hard.

He bobbed his head, relishing the heady taste on his tongue. Hollowing his cheeks he took Ciel further into his mouth, released him, licking around the head and underside. A pearl of pre-cum made its way down, and Sebastian followed it with his tongue.

Ciel was breathing hard, cheeks and chest rosy. His legs splayed wide apart, his asshole on display. Sebastian was ravenous, and yet he couldn't move. Eyes glued to the gorgeous boy beneath him.

''Sebastian,'' breathy, needy. God, this must be heaven. ''Kiss me,'' it wasn't a plea, but it was close enough, Ciel could've asked for anything, Sebastian would've gave it up with a smile. Nothing is easier than leaning in and capturing that wicked mouth with his. He groaned into the kiss, each one is better than its precursor. Sweeter, less frantic, deeper.

Ciel's wire-arms around his neck, pulling him closer, his fingers in Sebastian's hair. Sebastian's cock was so hard, he wanted Ciel so bad it hurt.

''Can I have you? Can I?''

Their gazes locked, blue depth sucking him in. ''Only if you love me.''

And by God he did.

The weather was warm, air moving inside from the open window. Cold on their flushed skins. Sebastian will remember this forever.

Ciel was hot and tight when Sebastian finally entered him. Too much, he had to count in his head so he wouldn't come immediately. Ciel clung to him, legs around Sebastian's waist, arms around his shoulders, nails in his flesh. 

Hips snapping forward, Sebastian lost himself in the feeling of being inside Ciel.  So good, so right and filthy and fucking amazing. Ciel's moans filled his ears, every thrust punched a melodious mewl out of Ciel. He was all Sebastian's, breathless with want, writhing, head thrown back and hair sticking to his skin. So gorgeous and owned.

''Mine, all mine,'' He chanted it with his thrusts, _mine mine mine_ , till he believed it. Ciel said _yes, yes, Sebastian I'm yours_. And Sebastian lost it, his vision whited out as he came. Violent shudders taking over his body, his seed filling Ciel up. Ciel came right after, his walls clamping down on Sebastian, milking him through his orgasm.

''You...still..have to buy me...a ring,'' Ciel said between pants. Sebastian laughed, happiness coursing through him.

''Anything you want,'' He promised.

Later that night, when Ciel crawled into his bed Sebastian worshiped him properly. Kissed every patch of skin, liked his spine and planted kisses on the dips of his back. Bit down into the enticing perky ass, painted marks on the insides of Ciel's marble thighs with tongue and lips.

He fucked Ciel from behind, harsher than the first time, sucked more kisses onto his back. Secret places that only he got to see. Skin that only he could reach and kiss.

''Ciel?''

Ciel stirred, nuzzling into Sebastian's chest where his head was rested. ''Hmm?''

Sebastian took small hand in his, kissed every finger. Cold metal, too big to fit the ring finger. Sebastian slid it on Ciel's thump instead. A ring that took all what he saved during the summer, silver with a jewel on top. Blue like Ciel's eyes, like Sebastian's heaven, like his hell.

Ciel shot up, stared at the ring then at Sebastian. ''You bought me a ring?''

''I love you,'' Sebastian said as an answer. Ciel's smile was blinding, even in the dark around them. His kiss kept breaking by laughter.

''You're cute,'' Ciel said around a smile. A happy start.

Sebastian will give his damn to get them a happy end, too.    

 

**Author's Note:**

> Tell me how you felt about this! I'm [Nisaki](https://nisaki-chan.tumblr.com) on tumblr, come say hi!


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